Reactive nanoparticles as destructive adsorbents for biological and chemical contamination

ABSTRACT

Compositions and methods for destroying biological agents such as toxins and bacteria are provided wherein the substance to be destroyed is contacted with finely divided metal oxide or hydroxide nanocrystals. In various embodiments, the metal oxide or metal hydroxide nanocrystals have reactive atoms stabilized on their surfaces, species adsorbed on their surfaces, or are coated with a second metal oxide. The desired metal oxide or metal hydroxide nanocrystals can be pressed into pellets for use when a powder is not feasible. Preferred metal oxides for the methods include MgO, SrO, BaO, CaO, TiO 2 , ZrO 2 , FeO, V 2 O 3 , V 2 O 5 , Mn 2 O 3 , Fe 2 O 3 , NiO, CuO, Al 2 O 3 , SiO 2 , ZnO, Ag 2 O, [Ce(NO 3 ) 3 —Cu(NO 3 ) 2 ]TiO 2 , Mg(OH) 2 , Ca(OH) 2 , Al(OH) 3 , Sr(OH) 2 , Ba(OH) 2 , Fe(OH) 3 , Cu(OH) 3 , Ni(OH) 2 , Co(OH) 2 , Zn(OH) 2 , AgOH, and mixtures thereof.

RELATED APPLICATION

[0001] This is a continuation of application Ser. No. 09/824,947, filedApr. 3, 2001, which is a continuation-in-part of application Ser. No.09/549,991, filed Apr. 14, 2000, incorporated by reference herein, whichis a continuation-in-part of application Ser. No. 09/153,437,incorporated by reference herein and filed Sep. 15, 1998, now U.S. Pat.No. 6,057,488.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention is broadly concerned with compositions andmethods for sorbing and/or destroying dangerous substances such aschemical and biological warfare agents. The methods of the invention arecarried out by simply contacting the target substance with particulatemetal oxide or metal hydroxide compositions. These compositions can beunmodified, or alternately, can be coated with a second metal oxide or ametal nitrate or mixture of metal nitrates, have reactive atoms ormixtures of reactive atoms stabilized on their surfaces, or have speciesadsorbed on their surfaces. In another embodiment, the particulate metaloxides or metal hydroxides (unmodified or modified) which can be formedinto pellets (e.g., by pressing or other methods such as by using abinder) which possess the same destructive abilities as the metal oxidesor metal hydroxide in powder form. Methods in accordance with theinvention require the use of minimal liquids, thus resulting in verylittle effluent. Furthermore, the particulate metal oxide or metalhydroxide compositions utilized in the methods of the invention are notharmful to equipment or to humans and can easily be used directly at thesite of contamination.

[0004] 2. Description of the Prior Art

[0005] The threat of biological and chemical warfare has grownconsiderably in recent times. Numerous countries are capable ofdeveloping deadly biological and chemical weapons. Some potentbiological agents include the following: bacteria such as Bacillusanthracis (anthrax) and Yersinia pestis (plague); viruses such asvariola virus (small pox) and flaviviruses (hemorrhagic fevers); andtoxins such as botulinum toxins and saxitoxin. Some potent chemicalagents include: blister or vesicant agents such as mustard agents; nerveagents such as methylphosphonothiolate (VX); lung damaging or chokingagents such as phosgene (CG); cyanogen agents such as hydrogen cyanide;incapacitants such as 3-quinuclidinyl benzilate; riot control agentssuch as CS (malonitrile); smokes such as zinc chloride smokes; and someherbicides such as 2,4-D (2,4-dichlorophenoxy acetic acid).

[0006] All of the above agents, as well as numerous other biological andchemical agents, pose a significant risk to private citizens as well asto military personnel. For example, vesicant agents burn and blister theskin or any other part of the body they contact, including eyes, mucusmembranes, lungs, and skin. Nerve agents are particularly toxic and aregenerally colorless, odorless, and readily absorbable through the lungs,eyes, skin, and intestinal track. Even a brief exposure can be fatal anddeath can occur in as quickly as 1 to 10 minutes. Biological agents suchas anthrax are easily disseminated as aerosols and thus have the abilityto inflict a large number of casualties over a wide area with minimallogistical requirements. Many biological agents are highly stable andthus can persist for long periods of time in soil or food.

[0007] There are currently two general types of decontamination methodsfor biological agents: chemical disinfection and physicaldecontamination. Chemical disinfectants, such as hypochlorite solutions,are useful but are corrosive to most metals and fabrics, as well as tohuman skin. Physical decontamination, on the other hand, usuallyinvolves dry heat up to 160° C. for 2 hours, or steam or super-heatedsteam for about 20 minutes. Sometimes UV light can be used effectively,but it is difficult to develop and standardize for practical use.

[0008] These methods have many drawbacks. The use of chemicaldisinfectants can be harmful to personnel and equipment due to thecorrosiveness and toxicity of the disinfectants. Furthermore, chemicaldisinfectants result in large quantities of effluent which must bedisposed of in an environmentally sound manner. Physical decontaminationmethods are lacking because they require large expenditures of energy.Both chemical and physical methods are difficult to use directly at thecontaminated site due to bulky equipment and/or large quantities ofliquids which must be transported to the site. Finally, while aparticular decontamination or disinfection method may be suitable forbiological decontamination, it is generally not effective againstchemical agents. There is a need for decontamination compounds which areeffective against a wide variety of both chemical and biological agents,have low energy requirements, are easily transportable, do not harm skinor equipment, and employ small amounts of liquids with minimal or noeffluent.

SUMMARY OF THE INVENTION

[0009] The present invention overcomes these problems and providescompositions and methods for sorbing (e.g., adsorption andchemisorption) and destroying biological and chemical agents. To thisend, the invention contemplates the use of finely divided nanoscalemetal oxide or metal hydroxide adsorbents. These adsorbents can be usedin an unmodified form or can be pelletized, coated with a second metaloxide or a metal nitrate, or have reactive atoms stabilized on theirsurfaces. These decontamination reactions can be carried out over a widerange of temperatures and can be conducted at the contaminated site.Furthermore, these adsorbents are not harmful to equipment or to humans.

[0010] In more detail, the nanoscale adsorbents used in the methods ofthe invention are formed from metal oxides or metal hydroxides selectedfrom the group consisting of MgO, CeO₂, CaO, TiO₂, ZrO₂, FeO, V₂O₃,V₂O₅, Mn₂O₃, Fe₂O₃, NiO, CuO, Al₂O₃, ZnO, SiO₂, Ag₂O, SrO, BaO, Mg(OH)₂,Ca(OH)₂, Al(OH)₃, Sr(OH)₂, Ba(OH)₂, Fe(OH)₃, Cu(OH)₃, Ni(OH)₂, Co(OH)₂,Zn(OH)₂, AgOH, and mixtures thereof. While conventionally preparedpowders can be used in the methods of the invention, the preferredpowders are prepared by aerogel techniques from Utamapanya et al., Chem.Mater., 3:175-181 (1991), incorporated by reference herein.

[0011] The adsorbents should have an average crystallite size of up toabout 20 nm, preferably from about 3-8 nm, and more preferably 4 nm, andexhibit a Brunauer-Emmett-Teller (BET) multi-point surface area of atleast about 70 m²/g, preferably at least about 100 m²/g, more preferablyat least about 120 m²/g. In terms of pore radius, the preferredadsorbents should have an average pore radius of at least about 45 Å,more preferably from about 50-100 Å, and most preferably from about60-75 Å.

[0012] These nanoscale adsorbents can be used alone and in their powderform, or they can be modified. For example, the finely divided particlesof the metal oxides or metal hydroxides can have at least a portion oftheir surfaces coated with a quantity of a second metal oxide differentthan the first metal oxide and selected from oxides of metals selectedfrom the group consisting of Ti, V, Fe, Cu, Ni, Co, Mn, Zn, Al, Ce, Sr,Ba, and mixtures thereof. In preferred forms, the coated metal oxideparticles comprise a first metal oxide selected from the groupconsisting of MgO and CaO, whereas the second metal oxide is preferablyZnO. In another embodiment, the first metal oxides described above arecoated with a mixture of metal nitrates such as those selected from thegroup consisting of Cu(NO₃)₂, Ce(NO₃)₃, AgNO₃, and mixtures thereof. Ina preferred embodiment, TiO₂ is coated with a mixture of cerium nitrateand copper nitrate to form [Ce(NO₃)₃—Cu(NO₃)₂]TiO₂.

[0013] For most efficient uses, the particles of the first metal oxideor metal hydroxide should have the average crystallite sizes andmulti-point surface areas set forth above. As is conventional in theart, the term “particles” is used herein interchangeably with the term“crystallite.” The second metal oxide or metal nitrates should be in theform of an extremely thin layer or coating applied onto the surface ofthe first metal oxide or metal hydroxide, thus giving an average overallsize for the composite of up to about 21 nm, more preferably from about5-11 nm, and most preferably about 5 nm. Generally, the first metaloxide or metal hydroxide should be present in substantial excessrelative to the second metal oxide or metal nitrate. Thus, the firstmetal oxide or metal hydroxide comprises from about 90-99% by weight ofthe total composite material, and more preferably from about 95-99% byweight. Correspondingly, the second metal oxide or metal nitrate shouldcomprise from 1-10% by weight of the total composite, and morepreferably from about 1-5% by weight. At least 25% of the surface areaof the first metal oxide or metal hydroxide particles should be coveredwith the second oxide or metal nitrate, and more preferably from about90-100% of this surface area should be covered.

[0014] The coated metal oxide or metal hydroxide particles orcrystallites of this embodiment are preferably fabricated by firstforming the very finely divided first particulate material using knownaerogel techniques. Thereafter, the second material is applied onto thesurface of the first metal oxide or metal hydroxide as an extremely thinlayer, e.g., a monolayer having a thickness on the order of less than 1nm. For example, nanocrystalline MgO can be prepared and then treatedwith an iron salt such as iron III (acetylacetonate)₃ with the ligandsbeing driven off by heating.

[0015] In another embodiment, the methods of the invention utilizeparticulate metal oxides having reactive atoms (different from thoseatoms making up the metal oxide) stabilized on the surfaces thereof. Inmore detail, the metal oxide particulates have oxygen ion moieties ontheir surfaces with reactive atoms interacted or chemisorbed with thosesurface oxygen ions. The metal oxide particles are, as with the twopreviously described embodiments, selected from the group consisting ofMgO, CeO₂, AgO, SrO, BaO, CaO, TiO₂, ZrO₂, FeO, V₂O₃, V₂O₅, Mn₂O₃,Fe₂O₃, NiO, CuO, Al₂O₃, ZnO, SiO₂, Ag₂O, and mixtures thereof.Furthermore, the particles should have the same average crystallitesizes and surface areas described above. Preferably, the reactive atomsutilized in this embodiment are selected from the group consisting ofhalogens and Group I metals. When halogens are the reactive atoms beingstabilized on the surfaces of the particles, the atoms can be atoms ofthe same halogen (e.g., only chlorine atoms), or the atoms can bemixtures of atoms of different halogens (e.g., both chlorine and bromineatoms on the metal oxide surfaces).

[0016] When stabilizing a Group I metal atom, the atom loading on themetal oxide should be from about 5-40% by weight, preferably from about10-15% by weight, and more preferably about 12% by weight, based uponthe weight of the atom-loaded metal oxide taken as 100%. Whenstabilizing either a Group I metal atom or a halogen atom, the atomloading on the metal oxide can also be expressed as a concentration ofatoms per unit of surface area of the metal oxide i.e., at least about 2atoms per square nanometer of metal oxide surface area, preferably fromabout 3-8 atoms per square nanometer of metal oxide surface area, andmore preferably from about 4-5 atoms per square nanometer of metal oxidesurface area. The preferred Group I metal is potassium, and thepreferred halogens are chlorine and bromine.

[0017] The surface-stabilized, reactive atom composites are formed byheating a quantity of particulate metal oxide particles to a temperatureof at least about 200° C., preferably at least about 300° C., and morepreferably to a level of from about 450 to about 500° C. Heating themetal oxide particles to these temperatures removes water from theparticles so that the final compositions have a surface hydroxylconcentration of less than about 5 hydroxyl groups per square nanometerof metal oxide surface area, and preferably less than about 4 hydroxylgroups per square nanometer of metal oxide surface area. The particlesare preferably allowed to cool to room temperature. The particles arethen contacted with a source of reactive atoms, e.g., a compound whichdissociates into reactive atoms under the proper reaction conditions.The reactive atoms interact with the metal oxide surface oxygen ions,thus stabilizing the atoms on the oxide surface. As used hereinafter,the terms “stabilized” and “stable” mean that, when the metal oxide-atomadducts are heated to a temperature of about 100° C., less than about10% of the total weight loss of the adduct is attributable to thereactive atoms desorbing.

[0018] In another embodiment, the methods of the invention utilizeparticulate metal oxides having species different than the metal oxideadsorbed on the surfaces thereof. The metal oxide particles are selectedfrom the group consisting of MgO, CeO₂, AgO, SrO, BaO, CaO, TiO₂, ZrO₂,FeO, V₂O₃, V₂O₅, Mn₂O₃, Fe₂O₃, NiO, CuO, Al₂O₃, ZnO, SiO₂, Ag₂O, andmixtures thereof. The particles should have the same average crystallitesizes and surface areas described above. Preferably, the adsorbedspecies are selected from the group consisting of oxides of Group Velements, oxides of Group VI elements, and ozone. Preferred oxides ofGroup V and VI elements are NO₂ and SO₂, respectively.

[0019] When adsorbing a species on the metal oxide surfaces, the speciesloading on the metal oxide should be from about 1-60% by weight,preferably from about 5-40% by weight, and more preferably about 15-25%by weight, based upon the weight of the adsorbed species-metal oxidetaken as 100%. The species loading can also be expressed as aconcentration of species molecules per unit of surface area of metaloxide. Preferably, there are at least about 2 molecules of the speciesadsorbed per square nanometer of metal oxide and more preferably atleast about 5 molecules. The adsorbed-species, metal oxide compositesare formed by contacting a quantity of the desired metal oxide (in anair evacuated flask) with the gaseous species. The sample is allowed toreact for about 30 minutes, after which time the excess gaseous speciesis pumped out.

[0020] In yet another embodiment, the methods of the inventioncontemplate forming the above metal oxide particles and compositesincluding those particles (i.e., unmodified, finely divided metal oxideor metal hydroxide particles, finely divided metal oxide or metalhydroxide particles coated with a second metal oxide, finely dividedmetal oxide particles having reactive atoms and mixtures of reactiveatoms stabilized on the surfaces thereof, and metal oxide particleshaving species adsorbed on the surfaces thereof) into pellets for usewhen powdered decontaminants are not feasible. These pellets are formedby pressing a quantity of one of these powdered metal oxide or metalhydroxide composites at a pressure of from about 50-6,000 psi, morepreferably from about 500-5000 psi, and most preferably at about 2,000psi. While pressures are typically applied to the powder by way of anautomatic or hydraulic press, one skilled in the art will appreciatethat the pellets can be formed by any pressure-applying means or bytumbling, rolling, or other means. Furthermore, a binder or filler canbe mixed with the adsorbent powder and the pellets can be formed bypressing the mixture by hand. Agglomerating or agglomerated as usedhereinafter includes pressing together of the adsorbent powder as wellas pressed-together adsorbent powder. Agglomerating also includes thespraying or pressing of the adsorbent powder (either alone or in amixture) around a core material other than the adsorbent powder.

[0021] In order to effectively carry out the methods of the invention,the pellets should retain at least about 25% of the multi-point surfacearea/unit mass of the metal hydroxide or metal oxide (whichever was usedto form the pellet) particles prior to pressing together thereof. Morepreferably, the multi-point surface area/unit mass of the pellets willbe at least about 50%, and most preferably at least about 90%, of themulti-point surface area/unit mass of the starting metal oxide or metalhydroxide particles prior to pressing. The pellets should retain atleast about 25% of the total pore volume of the metal hydroxide or metaloxide particles prior to pressing thereof, more preferably, at leastabout 50%, and most preferably at least about 90% thereof. In the mostpreferred forms, the pellets will retain the above percentages of boththe multi-point surface area/unit mass and the total pore volume. Thepellets normally have a density of from about 0.2 to about 2.0 g/cm³,more preferably from about 0.3 to about 1.0 g/cm³, and most preferablyfrom about 0.4 to about 0.7 g/cm³. The minimum surface-to-surfacedimension of the pellets (e.g., diameter in the case of spherical orelongated pellet bodies) is at least about 1 mm, more preferably fromabout 10-20 mm.

[0022] In carrying out the methods of the invention, one or more of theabove described metal oxide particle composites are contacted with thetarget substance to be sorbed, decontaminated or destroyed underconditions for sorbing, decontaminating or destroying at least a portionof the substance. The methods of the invention provide for destructivelyadsorbing a wide variety of chemical agents, including agents selectedfrom the group consisting of acids, alcohols, compounds having an atomof P, S, N, Se, or Te, hydrocarbon compounds, and toxic metal compounds.The methods of the invention also provide for biocidally adsorbing awide variety of biological agents including bacteria, fungi, viruses,rickettsiae, chlamydia, and toxins. Utilizing the metal oxideparticulate composites in accordance with the methods of the inventionis particularly useful for destructively adsorbing biological agentssuch as bacteria (e.g., gram positive bacteria like B. subtilis, B.globigii and B. cereus or gram negative bacteria like E. coli, and E.Herbicola).

[0023] The composites are also useful for adsorbing toxins such asAflatoxins, Botulinum toxins, Clostridium perfringens toxins,Conotoxins, Ricins, Saxitoxins, Shiga toxins, Staphylococcus aureustoxins, Tetrodotoxins, Verotoxins, Microcystins (Cyanginosin), Abrins,Cholera toxins, Tetanus toxins, Trichothecene mycotoxins, Modeccins,Volkensins, Viscum Album Lectin 1, Streptococcal toxins (e.g.,erythrogenic toxin and streptolysins), Pseudomonas A toxins, Diphtheriatoxins, Listeria monocytogenes toxins, Bacillus anthracis toxiccomplexes, Francisella tularensis toxins, whooping cough pertussistoxins, Yersinia pestis toxic complexes, Yersinia enterocolyticaenterotoxins, and Pasteurella toxins. In another embodiment, the methodsof the invention provide for the destructive adsorption of hydrocarboncompounds, both chlorinated and non-chlorinated.

[0024] The contacting step can take place over a wide range oftemperatures and pressures. For example, the particulate metal oxide ormetal hydroxide composites can be taken directly to a contaminated siteand contacted with the contaminant and/or contaminated surfaces atambient temperatures and pressures. Alternately, the contacting step canbe carried out at a temperature of from about −40-600° C. If thecontacting step is to be carried out under ambient temperatures,preferably the reaction temperature range is from about 10-200° C. Ifthe contacting step is to be carried out under high temperatureconditions, then preferably the temperature range for the reaction isfrom about 350-550° C. If the contacting step is carried out underambient conditions, the particulate metal oxide or metal hydroxidecomposites should be allowed to contact the target substance for atleast about 0.5 minutes, preferably from about 1-100 minutes, and morepreferably from about 1.5-20 minutes. If the contacting step is carriedout under high temperatures conditions, then the particulate metal oxideor metal hydroxide composites should be allowed to contact the targetsubstance for at least about 4 seconds, preferably for about 5-20seconds, and more preferably for about 5-10 seconds.

[0025] If the target substance is a biological agent, the contactingstep results in at least about a 80% reduction in the viable units ofthe biological agent, preferably at least about a 90% reduction, andmore preferably at least about a 95% reduction. If the target substanceis a chemical agent, the contacting step results in at least about 90%reduction in the concentration of the chemical agent, preferably atleast about a 95% reduction, and more preferably at least about a 99%reduction.

[0026] Those skilled in the art will appreciate the benefits provided bythe methods of the invention. In accordance with the invention, militarypersonnel can utilize the particulate metal oxides, metal hydroxides,and composites thereof to neutralize highly toxic substances such asnerve agents and biological agents. These particles and composites canbe utilized in their non-toxic ultrafine powder form to decontaminateareas exposed to these agents, or the powders or highly pelletizedcomposites can be utilized in air purification or water filtrationdevices. Other countermeasure and protective uses for the metal oxide ormetal hydroxide particles and composites of the particles includepersonnel ventilation systems and wide-area surface decontamination.Furthermore, the metal oxide or metal hydroxide composites remainairborne for at least one hour, thus providing effective airbornedecontamination of chemical or biological agents. Alternately, thecomposites can be formulated into a cream or incorporated in or onclothing in order to provide protection to personnel at risk ofcontacting a dangerous agent.

[0027] Unlike currently available decontamination methods, the methodsof the invention utilize composites that are non-toxic to humans andnon-corrosive to equipment, thus permitting the decontaminated equipmentto be put back into use rather than discarded. Furthermore, because thecomposites are easy to disperse and readily transportable, and becauselittle or no water is required to practice the invention, it isrelatively simple to destroy the contaminants at the contaminated site.

BRIEF DESCRIPTION OF THE DRAWINGS

[0028]FIG. 1 is a graph illustrating the particle size distribution andparticle concentration for B. globigii without the addition of Cl/AP-MgOpowder;

[0029]FIG. 2 shows the baseline decay curve for B. globigii;

[0030]FIG. 3 is a graph depicting the Cl/AP-MgO concentration withrespect to time when B. globigii was exposed to a low concentration ofCl/AP-MgO;

[0031]FIG. 4 is a graph illustrating the particle size distribution forthe mixture of powder and B. globigii when B. globigii was exposed to alow concentration of Cl/AP-MgO powder;

[0032]FIG. 5 shows the decay curve for B. globigii when B. globigii wasexposed to a low concentration of Cl/AP-MgO;

[0033]FIG. 6 is a graph depicting the Cl/AP-MgO concentration withrespect to time when B. globigii was exposed to a high concentration ofCl/AP-MgO;

[0034]FIG. 7 is a graph depicting the particle size distribution for amixture of powder and B. globigii when B. globigii was exposed to a highconcentration of Cl/AP-MgO;

[0035]FIG. 8 is a graph illustrating the decay curve for B. globigiiwhen B. globigii was exposed to a high concentration of Cl/AP-MgO; and

[0036]FIG. 9 is a graph illustrating the destructive adsorption ofparaoxon on AP-MgO, I/AP-MgO, and Cl/AP-MgO.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] The following examples set forth preferred methods in accordancewith the invention. It is to be understood, however, that these examplesare provided by way of illustration and nothing therein should be takenas a limitation upon the overall scope of the invention. In theseexamples, “AP-MgO” and “AP-CaO” refer to the respective aerogel (orautoclave) prepared oxides. “CP-MgO” and “CP-CaO” refer to therespective oxides produced by conventional techniques.

EXAMPLE 1 Preparation of MgO Samples

[0038] 1. AP-MgO

[0039] Highly divided nanocrystalline Mg(OH)₂ samples were prepared bythe autoclave treatment described by Utamapanya et al., Chem. Maier.,3:175-181 (1991), incorporated by reference herein. In this procedure,10% by weight magnesium methoxide in methanol solution was prepared and83% by weight toluene solvent was added. The solution was thenhydrolyzed by addition of 0.75% by weight water dropwise while thesolution was stirred and covered with aluminum foil to avoidevaporation. To ensure completion of the reaction, the mixture wasstirred overnight. This produced a gel which was treated in an autoclaveusing a glass lined 600 ml capacity Parr miniature reactor. The gelsolution was placed within the reactor and flushed for 10 minutes withnitrogen gas, whereupon the reactor was closed and pressurized to 100psi using the nitrogen gas. The reactor was then heated up to 265° C.over a 4 hour period at a heating rate of 1° C./min. The temperature wasthen allowed to equilibrate at 265° C. for 10 minutes (final reactorpressure was about 800-1000 psi). At this point, the reactor was ventedto release the pressure and vent the solvent. Finally, the reactor wasflushed with nitrogen gas for 10 minutes. The Mg(OH)₂ particles werethen thermally converted to MgO. This was accomplished by heating theMg(OH)₂ under dynamic vacuum (10⁻² Torr) conditions at an ascendingtemperature rate to a maximum temperature of 500° C. which was held for6 hours resulting in AP-MgO with a BET surface area of 300-600 m²/g andan average crystallite size of 4 nm. Further details about the MgOpreparation can be found in PCT Publication WO 95/27679, alsoincorporated by reference herein.

[0040] 2. CP-MgO

[0041] CP-MgO samples were prepared by boiling commercially availableMgO (Aldrich Chemical Company) for one hour, followed by microwavedrying of the sample. The sample was then dehydrated under vacuum at500° C. resulting in CP-MgO with a BET surface area of 130-200 m²/g andan average crystallite size of 8.8 nm.

EXAMPLE 1A Preparation of AP-CaO and CP-CaO

[0042] AP-CaO was prepared in a manner similar to the preparation ofAP-MgO as described in Example 1 with the following exceptions: 8 g. ofcalcium metal and 230 ml of methanol were allowed to react; and 180 mlof toluene and 1.2 ml of distilled water were added to the 20 g ofcalcium methoxide obtained.

[0043] AP-CaO (N₂ dehydrated) was prepared in a similar manner with theexception that the sample was dehydrated by heating to a temperature of500° C. while passing N₂ gas over the sample. CP-CaO (vacuum dehydrated)was prepared in the same manner as CP-MgO (described in Example 1, Part2).

EXAMPLE 1B Preparation of Fe₂O₃/MgO Composites

[0044] Mg(OH)₂ particles were first thermally converted to MgO, followedby deposition of iron oxide to provide the complete composite. Theinitial thermal conversion of magnesium hydroxide to MgO was carried outby heating the magnesium hydroxide under dynamic vacuum conditions at anascending temperature rate to a maximum temperature of 500° C., whichwas held for 6 hours. Most of the dehydration was found to occur attemperatures between 200° C. and 320° C. IR and x-ray diffractionstudies confirm virtually complete conversion of the Mg(OH)₂ to MgO.

[0045] Iron oxide was deposited on the nanoscale MgO particles bycarrying out a direct reaction between activated MgO and iron III(acetylacetonate)₃, in tetrahydrofuran at room temperature under 1atmosphere of helium.

[0046] In a typical preparation, 0.3 grams of Mg(OH)₂ was heated undervacuum (10⁻³ Torr.) at an ascending temperature rate of 1° C./min. to500° C., which was held for 6 hours to assure complete conversion toMgO, followed by cooling to room temperature.

[0047] The evacuated system was then filled with helium at 1 atm.pressure. Two milliliters of 0.25 M iron m (acetylacetonate)₃ intetrahydrofuran (THF) solution (previously prepared under argon bydissolving 4.5 g of iron III (acetylacetonate)₃ in 50 ml of THF) wasintroduced by a syringe. The amount of iron III (acetylacetonate)₃solution used provided the MgO surfaces with 1.4 iron III(acetylacetonate)₃ molecules for each surface OH group. Theconcentration of surface OH groups for the autoclave-prepared MgO wasfound to be 3.6 OH groups/nm². The reaction mixture was stirredovernight to allow a complete reaction at room temperature. The reactedFe₂O₃/MgO composite was then removed, filtered using regular filterpaper, washed with THF to remove any residual iron III(acetylacetonate)₃, and dried in air for ten minutes.

[0048] IR spectra of the resultant dry product showed bands for theacetylacetonate species, indicating the existence of someacetylacetonate ligands bound to the surfaces of the MgO. This productwas heated again under vacuum (10⁻³ Torr.) at 500° C. to remove theseligands.

EXAMPLE 2 Halogenated Metal Oxides

[0049] The following procedures were followed to prepare halogenatedmetal oxides:

[0050] 1. Chlorinated Metal Oxides

[0051] In order to prepare Cl/MgO or Cl/CaO, metal oxide samples(weighing from about 0.30 to about 1.0 g each) were placed in a Schlenktube (340 ml vacuum tight glass tubes). Each sample tube was evacuatedat room temperature and an excess of chlorine gas was allowed to enterthe tube at a pressure of about 1 atm of chlorine. The amount ofchlorine gas was determined to be an excess amount when the inlet gasremained green. The samples became hot to the touch when the chlorineentered the tubes, indicating that a reaction was taking place. Thereaction was complete within one to two minutes, but each sample wasallowed to stand for approximately 30 minutes before removal from thetube.

[0052] 2. Brominated Metal Oxides

[0053] Br/MgO and Br/CaO were prepared in a manner similar to thatdescribed under Part 1. An excess of bromine gas was allowed to enter aSchlenk tube which contained from 0.30 to 1.0 g of the particular metaloxide sample at the vapor pressure of bromine at room temperature. Theamount of bromine gas was determined to be an excess amount when theinlet gas remained dark red. The reaction was complete within severalminutes, but each sample was allowed to stand for approximately 30minutes before removal from the tube.

[0054] 3. Iodinated Metal Oxides

[0055] I/MgO and I/CaO were prepared by placing 1.0 g of the metal oxidein a Schlenk tube along with 1.0 g of iodine. The air was evacuated fromthe tube, the stopcock was closed, and the mixture was heated to 90-100°C. The iodine vaporized and deposited onto the oxide particles. Thesample was allowed to stand for about 30 minutes before removal from thesample tube.

EXAMPLE 3

[0056]1. Preparation of Bacillus globigii Culture

[0057]B. globigii was grown for 72 hours at 35° C. on Casitone nutrientagar plates (150 mm, Remel Co., Lenexa, Kans.) containing 0.002% MnCl₂to induce approximately 80% sporulation. For each test, cells wereharvested into 25 ml sterile phosphate buffer solution (PBS) andcentrifuged at 3000 rpm for 15 minutes. The supernatant was decanted,and the cells were resuspended in 25 ml sterile PBS and vortexedthoroughly. The suspension was diluted to 0.1 O.D._(590 nm) (i.e., thesuspension was diluted with PBS to 0.1 optical density at the 590wavenumber) for dissemination using a Bausch and Lomb Spec-20spectrophotometer.

[0058] 2. Baseline Decay Characterization for B. globigii

[0059] A 0.1 O.D._(590 nm) suspension of B. globigii was disseminatedfor 30 seconds using a BGI six jet collision nebulizer (CH Technologies,Westwood, N.J.) at 40 psi in a Bioaerosol test chamber. The chamber airwas sampled for 60 minutes at a rate of 50 L/min. using two NewBrunswick Slit-to-Agar Biological Air Samplers (New Brunswick ScientificCo., Edison, N.J.) with Casitone agar petri plates. The sampling began 1minute after dissemination was stopped in order to allow theconcentration of B. globigii to reach homogeneity in the chamber. AClimet CI-500 aerosol particle sizer (Climet Instrument Co., Redlands,Calif.) was used to track the particle size distribution throughout thetest (See FIG. 1). After the 60 minute sampling, the chamber air waspurged clean, and the agar plants were removed and incubated for 15hours at 35° C. Colonies were counted after the incubation period, andthe baseline curve for B. globigii was established (See FIG. 2).

[0060] 3. B. globigii Dissemination Followed by a Low ConcentrationPowder Dispersion

[0061]B. globigii was disseminated following the procedures described inPart 2 of this example. One minute after dissemination, sampling wascommenced using the New Brunswick air samplers. Sampling was continuedfor 60 minutes. Five minutes after sampling was commenced, dispersion ofCl/AP-MgO powder (prepared as described in Example 2, Part 1) wasinitiated using a GEM-T air mill powder disperser (Coltec IndustrialProducts, Inc., Newtown, Pa.) and a vibrating spatula (Mettler Toledo,Highstown, N.J.). The powder was dispersed at a pressure of 40 psi untilthe concentration of powder in the air chamber reached approximately 4-5mg/m³ as indicated by a TSI Dustrak aerosol mass monitor (TSI, Inc., St.Paul, Minn.). These results are shown in FIG. 3. The particle sizedistributions were tracked using the Climet CI-500 (See FIG. 4). At thispowder concentration, the air mill was stopped.

[0062] At the end of the 60 minute sampling period, the chamber air waspurged clean, and the Casitone agar plates were removed and incubatedfor 15 hours at 35° C. Colonies were counted after the incubationsperiod and a decay curve for B. globigii was determined (See FIG. 5).

[0063] 4. B. globigii Dissemination Followed by a High ConcentrationPowder Dispersion

[0064] The procedure described in Part 3 of this example was repeatedwith the exception that the powder was dispersed to a concentration ofapproximately 20 mg/M³, as shown in FIG. 6. FIG. 7 sets forth theparticle size distribution and FIG. 8 sets forth the decay curve for B.globigii with a high concentration of Cl/AP-MgO powder dispersion.

[0065] 5. Results and Discussion

[0066] The results of the tests conducted in Parts 2-4 of this exampleare shown in FIGS. 1-8. In FIGS. 2, 5, and 8, the y-axis indicates thenumber of B. globigii colony forming units (CFU's) collected in 100liters of air at the given time point indicated on the x-axis. CFUmeasurements of 200 indicate that there were too many CFRs to count, andthus the maximum number of 200 was assigned. In FIG. 2, the baselinedecay curve indicates that the concentration of viable cells in thechamber remained relatively high, starting at above 200 CFU per 100liters of air sampled and decreasing to approximately 65 CFU per 100liters of air sample during an one hour period. In the presence of a lowconcentration of Cl/AP-MgO powder, the decay curve of B. globigiiindicates that the CFUs started high at about 180 CFU per 100 liters ofair sampled and decreased to less than 20 CFU per 100 liters of airsampled in about 23 minutes (FIG. 5). Finally, the decay curve of B.globigii in the presence of a high concentration of Cl/AP-MgO powderindicates that the CFUs started off very high at above 200 CFU per 100liters of air sampled and decreased sharply to less than 20 CFU per 100liters of air sample in about 20 minutes (FIG. 8). A comparison of thedecay curves of B. globigii (FIGS. 2, 5, and 8) indicates that thepresence of metal oxide nanocrystals having reactive atoms stabilized ontheir surfaces has a significant impact on the number of viable cellsrecovered from the chamber environment. The data from Parts 3 and 4above show that, as the concentrations of powder are increased, a morerapid decrease in the recovery of viable cells is obtained.

EXAMPLE 4A

[0067]Bacillus cereus bacterial endospores were grown and placed inwater to form a suspension. A sterile nitrocellulose filter paper (3 cmdiameter) was placed on a sterile rack, and 200 μl of the aqueous sporesuspension was distributed onto the filter paper. The filter was airdried for 2-4 hours. The dried filter paper was placed in a sterilebeaker, and 10 ml of LB (Luria and Bertani) broth (containing 10 g/Ltryptone, 5 g/L yeast extract, and 10 g/L sodium chloride, pH adjustedto 7 with 5 N NaOH, and sterilized by pressurizing to about 1500 psi)were placed in another sterile beaker. The latter beaker was coveredwith aluminum foil. One gram of CP-CaO, was spread on the filter paperso that all of the paper was covered, aluminum foil was placed on top ofthis beaker, and the beaker was allowed to stand for 2 hours. Usingtweezers, the filter paper was removed and excess nanoparticle powdergently shaken off. The filter paper was immersed in the LB brothsolution for 10 minutes with occasional swirling. Ten μl of the LB brothsolution was extracted by a sterile syringe and distributed evenly on aBenzer agar culture plate using a sterile L-shaped glass piece. The lidwas placed on the agar plate, and the sample was incubated for 12 hoursat 37° C. Three agar plates were prepared for each test. Afterincubation, the number of visible, living bacterial colonies wascounted, and the percent killed or biocidally adsorbed (reduced) wasdetermined using the following equations:

Average Number of Colonies=n _(avg)=(n ₁ +n ₂ +n ₃)/3

% of Microorganisms Reduced=n_(%)=(n _(c) −n _(E))/n_(c)×100,

[0068] where n_(E)=average number of colonies on experimental plates,and

[0069] where n_(c)=average number of colonies on control plates.

[0070] The above procedures were repeated using Cl/AP-MgO, I/AP-MgO,AP-CaO with vacuum dehydration, and AP-CaO with N₂ dehydration in placeof CP-CaO. The results are set forth in Tables 1 and 2 below: TABLE 1Results of two hour^(a) exposure - raw data.^(b) Number of Reagentcolonies on each plate Average % Reduced Control 78(72) 40(99) 87 68(80)0% AP— 37 24 32 31 64 CaO(vac) AP— 18 29 34 27 68 CaO(N₂) CP—CaO 49(72)31(73) 45(81) 42(75) 39(12) AP—MgO— 4(0) 3(8) 5(22) 4(10) 94(88) Cl₂AP—MgO—I₂ 32(85) 48(83) 44(100) 41(91) 40(−7)^(c)

[0071] TABLE 2 Results of two hour^(a) exposure - raw data. Number ofReagent colonies on each plate Average % Reduced Control 500 652 736 6330% AP—MgO— 60 50 46 52 95 Br₂

EXAMPLE 4B

[0072] This experiment was conducted to determine the effect of exposingB. cereus to nanocrystalline metal oxides for varying lengths of time.The procedure described in Example 4 was repeated using Cl/AP-MgO powderand contacting the Cl/AP-MgO powder with the B. cereus for 0 (control),20, 40, 60, 80, and 100 minutes. The results of this set of tests areset forth in Table 3. TABLE 3 Results of variable time exposure forCl/AP—MgO adduct. Time of Exposure^(a) Number of (min) colonies on eachplate Average % Reduced 0(control) 100 107 120 109 0% 20 5 4 8 6 95 40 63 14 8 93 60 3 4 1 3 98 80 5 6 4 5 95 100  8 5 3 5 95

[0073] Discussion

[0074] The results of the tests conducted in Examples 4A and 4B confirmthat Cl/AP-MgO is a very effective reagent for the biocidal destructionof B. cereus spores and supports the data reported in the previousexamples above on the biocidal destruction of B. globigii. Furthermore,Cl/AP-MgO acts rapidly, and even a 20 minute exposure was enough forefficient decontamination. Br/AP-MgO and AP-CaO were also quiteeffective in their biocidal abilities.

EXAMPLE 5

[0075]0.1 g of AP-MgO, I/AP-MgO, or Cl/AP-MgO was placed in a flaskequipped with a magnetic stirrer with 100 ml of pentane. A VX chemicalagent mimic, paraoxon (4.5 μl), was added to the flask, with 2 ml of theresulting sample being withdrawn and the UV spectrum taken at 2, 5, 10,15, 20, 40, 60, 80, 100, and 120 minutes after addition of the paraoxon.These results are illustrated in FIG. 9 and indicate that all three ofthe metal oxide samples worked well at destructively adsorbing theparaoxon. Upon reaction with paraoxon, the color of the sample (AP-MgO)changed from slightly grayish to bright yellow.

[0076] After the destructive adsorption of paraoxon was carried out,quantities of the AP-MgO/paraoxon samples were placed in solvents(methylene chloride or toluene) and sonicated for 30 minutes. Aftersonication, some of the liquid was removed from each sample and testedby GC-MS. The GC-MS results did not show the presence of paraoxon, thusproviding evidence that the paraoxon was destructively adsorbed by themetal oxide samples. Similar results have been achieved when usingnon-modified nanocrystalline metal oxide particles to destructivelyadsorb 2-chloroethyl ethyl sulfide (2-CEES),diethyl4-nitrophenylphosphate (paraoxon), and dimethylmethylphosphonate(DMMP) as reported in U.S. patent application Ser. No. 08/914,632(continuation-in-part of U.S. patent application Ser. No. 08/700,221),incorporated by reference herein.

EXAMPLE 6

[0077] In order to prepare metal oxide particles (e.g., AP-MgO, AP-CaO,etc.) having species adsorbed on the surfaces of the particles, 10 gramsof the desired metal oxide is placed on a Schlenk flask. The air isevacuated, and the gaseous species is introduced. The sample is allowedto react for about 30 minutes, after which time the excess gaseousspecies is pumped out. Gaseous species which can be adsorbed on thesurfaces of metal oxide particles include oxides of Group V and VIelements (such as NO₂ and SO₂, respectively) and ozone.

EXAMPLE 7

[0078] 1. Materials

[0079] Aflatoxins are toxic and carcinogenic substances produced bycertain strains of the molds Aspergillus flavus and Aspergillusparasiticus. For these examples, Aflatoxins were obtained from SigmaChemical Company (St. Louis, Mo.). A 1,000 ppm stock solution of AB1 wasprepared in acetonitrile. Serial dilutions of the stock solutions weremade to obtain 100 ppm, 10 ppm, 1 ppm, 100 ppb, and 10 ppb workingstandard solutions. The nanoparticles evaluated for their detoxificationcapabilities were CP-MgO—Br₂ (100% saturation, i.e., 15% by weightbromine, AP-CaO—Cl₂ (100% saturation, 13% by weight chlorine), andAP-MgO—Cl₂ (100% saturation, 13% by weight chlorine). Appropriatecontrol nanoparticles (non-halogenated nanoparticles and commercial MgOor CaO), positive control (ABI without exposure to nanoparticles) andnegative control (nanoparticle treatment only) were also evaluated inthese studies.

[0080] 2. Experimental Procedure

[0081] Fifty microliters of 10 ppm, 1 ppm, 100 ppb, and 10 ppb AB1solutions were spiked onto a filter paper and placed in a glass jar. Thefilter paper was then exposed to the appropriate nanoparticles for 1minute, and the glass jar was shaken to ensure uniform exposure to thenanoparticles. The filter paper was removed from the jar, shaken to dustoff the nanoparticles, and placed in an Agri-Screen (obtained fromNeogen, Lansing, Mich.) solvent extraction bottle for 1 minute withfrequent mixing of the bottle content. Approximately 2 ml of theextraction solvent was then passed through a syringe equipped with glasswool and collected in a sample collection bottle.

[0082] Following the Aflatoxin AB1 extraction, an Agri-Screen kit (whichincluded a conjugate solution, a stop solution, and a substrate) wasused to screen for residual Aflatoxin in the extraction solvent. AnAgri-Screen kit is a competitive, direct enzyme-linked immunosorbentassay (CD-ELISA) that allows the qualitative, visible testing of asample against a known control concentration. Free toxin, both in thesample and in the control, is allowed to compete with the enzyme-labeledtoxin (conjugate) for the antibody binding sites. After a wash step, thesubstrate is added, and it reacts with the bound enzyme conjugate toproduce a blue color. The color of the sample is then visually comparedto the color of the control. If the sample color is more blue than thecontrol, then it contains less toxin than the control. If the samplecolor is less blue than the control, then it contains more toxin thanthe control.

[0083] Thus, the Agri-Screen procedure in this example consisted ofadding 3 drops of the sample solvent to the well followed by theaddition of 2 drops of a conjugate solution. The wells were thenincubated for 5 minutes at room temperature. Three drops of substratewere added to the wells and incubated for 5 minutes at room temperaturefollowed by the addition of a stop solution. The contents of the wellwere mixed with the Pasteur pipette, and the color of the solution inthe well was recorded. The color of the solution in the well wascompared to that of the solution in the control wells (20 ppb AflatoxinB1).

[0084] 3. Results

[0085] The results of these tests are summarized in Table 4. Thehalogenated metal oxide nanoparticles inhibited the growth of toxins.These results, when viewed with the results of the previous examples,indicate that the halogenated metal oxide nanoparticles are effective asdecontaminating agents active against a broad class of both chemical andbiological species.

[0086] The exact mechanism by which decontamination occurs is not known.However, it is believed that the nanoparticles are attacking either theketone or methoxy group of the Aflatoxin (see Formula I). TABLE 4 Effectof Nanoparticles on Aflatoxin B1. Re- Re- Nanoparticle sult Nanoparticlesult Kit control + Nanoparticle only (control) −− Aflatoxin B1 (AB1) 10ppm + CM-MgO (10 ppm AB1) −− AP-MgO-Cl₂ −− (10 ppm AB1) CM-MgO (1 ppmAB1) −− AP-MgO-Cl₂ (1 ppm AB1) −− CM-MgO (100 ppb AB1) −− AP-MgO-Cl₂ −−(100 ppb AB1) CM-MgO (10 ppb AB1) −− AP-MgO-Cl₂ (10 ppb AB1) −− CP-MgO(10 ppm AB1) − CM-CaO (10 ppm AB1) −− CP-MgO (1 ppm AB1) − CM-CaO (1 ppmAB1) −− CP-MgO (100 ppb AB1) − CM-CaO (100 ppb AB1) −− CP-MgO (10 ppbAB1) − CM-CaO (10 ppb AB1) −− CP-MgO-Br₂ (10 ppm AB1) −− AP-CaO (10 ppmAB1) −− CP-MgO-Br₂ (1 ppm AB1) −− AP-CaO (1 ppm AB1) −− CP-MgO-Br₂ (100ppb AB1) −− AP-CaO (100 ppb AB1) −− CP-MgO-Br₂ (10 ppb AB1) −− AP-CaO(10 ppb AB1) −− AP-MgO (10 ppm AB1) −− AP-CaO-Cl₂ (10 ppm AB1) −− AP-MgO(1 ppb AB1) −− AP-CaO-Cl₂ (1 ppm AB1) −− AP-MgO (100 ppb AB1) −−AP-CaO-Cl₂ −− (100 ppb AB1) AP-MgO (10 ppb AB1) −− AP-CaO-Cl₂ (10 ppbAB1) −−

[0087] Formula IV

EXAMPLE 8

[0088] 1. Procedure

[0089] In this test, metal oxide powders (in the amounts shown in Table5) were added to 1 liter of distilled water contaminated with E. coli(ATCC#3000, approximately 400 μl of a fresh, overnight culture).Controls (200 μl) were plated on nutrient agar before (time equal zero)and during the test to determine a baseline. At the given time interval,200 μl of the decontaminated water was sampled and plated on nutrientagar and incubated for 24 hours. Plates were counted and compared to thecontrols to determine the percent kill.

[0090] 2. Results

[0091] The metal oxide nanoparticles were successful in decontaminatinggram-negative. bacteria such as E. coli. Table 5 compares the threedifferent formulations of metal oxide or hydroxide nanoparticles. Highsurface area AP-MgO (greater than about 300 m²/g) and ZnO (greater thanabout 130 m²/g) samples were very effective at destructively sorbing theE. coli. TABLE 5 Metal Oxide AP—Ca(OH)₂ ZnO ZnO ZnO AP—MgO AP—MgOSurface area 60 m²/g 153 m²/g 153 m²/g 153 m²/g 642 m²/g 452 m²/g Amount0.75 g 1 g 1 g 0.5 g 1 g 1 g Time (minutes) Percent Kill Percent KillPercent Kill Percent Kill Percent Kill Percent Kill 15  98 99.6 100 61 54  60 30 100 99 100 63 100 100 45 100 99.8 100 73 100 100 60 100 96.7100 48 100 100

EXAMPLE 9

[0092]1. Preparation of ZnO-Coated AP-MgO (hereinafter referred to asAP-MgO/ZnO) In this procedure, 2.28 g of zinc acetate was dissolved inapproximately 200 ml of ethanol and 6 ml of distilled water. Thissolution was then added to 14.5 g of AP-Mg(OH)₂. After nitrogen wasintroduced into the mixture for 20 minutes, the flask was capped andleft to stir overnight. The sample was then filtered, washed withethanol, and filtered again. The filtered product, ZnO-coatedAP-Mg(OH)₂, was then activated using a dehydrator to produce ZnO-coatedAP-MgO nanoparticle powder. Approximately 10 g of ZnO-coated AP-MgO of 5mole percent by mass ZnO was obtained. The resulting BET surface areawas 446 m²/g.

[0093] 2. Preparation of CuO

[0094] Under argon, 1.50 g (0.0112 mole) of copper (II) chloride(obtained from Sigma Aldrich) was added to a 250 ml round bottom flask.This was then dissolved with 70 ml absolute ethanol (obtained fromMcCormick) to form a clear green solution. Next, 0.0224 mole sodiumhydroxide (obtained from Fisher) was dissolved in absolute ethanol andwas then added dropwise to the clear green solution to form the copperhydroxide gel. The reaction was stirred at room temperature for 2 hours.During this time, the reaction mixture formed a blue-green gel. Afterthe reaction was complete, the solution was filtered and washed withwater to remove the sodium chloride. The copper hydroxide was thenair-dried on the frit, to give a 90% yield. Data from thermalgravimetric analysis (TGA) confirmed that the copper hydroxide to copperoxide conversion occurred between 190-220° C. The dry copper hydroxidepowder was then placed into a Schlenk tube, connected to a flow of argonand surrounded by a furnace. The furnace was connected to a temperaturecontroller, and it was heated at 250° C. for 15 minutes. After the heattreatment was complete, the furnace was turned off and allowed to coolto room temperature. The copper oxide powder was black with a BETspecific surface area of 135 m²/g.

[0095] 3. Preparation of [Ce(NO₃)₃—Cu(NO₃)₂]TiO₂

[0096] In this procedure, 211 ml of neat titanium (IV) butoxide wasadded to 800 ml of methanol and flushed with nitrogen while stirring for10 minutes in a round bottom flask. A second, water-containing solution,was then prepared with 300 ml of methanol, 45 ml of distilled water, and2.2 ml of nitric acid. This solution was added dropwise to the stirringbutoxide solution. A gel slowly formed and was allowed to age overnight.Once the gel had aged, methanol was added at a 1:1 ratio and mixed, thusforming a solution that was spray dried (Buchi 190) with an inlettemperature of 200° C. and an outlet temperature of 80° C. Thespray-dried powder was collected and washed in 800 ml of distilled waterovernight and centrifuged to remove any excess solvent. The TiO₂ wasdried in an oven to remove any excess water. Approximately 20 g of TiO₂was obtained, and the resulting BET surface area was 194.2 m²/g.

[0097] Ten grams of TiO₂ was then coated with Ce(NO₃)₃ and Cu(NO₃)₂. Toaccomplish this, 0.544 g of Ce(NO₃)₃ and 0.291 g of Cu(NO₃)₂ wereweighed out in a dry flask, and 100 ml of TF was then added to dissolvethe nitrates. Next, 10 g of TiOwas added, and the solution was stirredfor 2 hours. The TiO₂ was allowed to settle for approximately one hourafter which the THF was decanted off the solution. The flask was thenstopped and put on a vacuum line overnight to remove the remainder ofthe THF. After the sample vacuum step was completed, the sample wasplaced uncapped in a drying oven set at 110° C. for 1 hour. Theresulting BET surface area of the 1 mole % Ce(NO₃)₃/1 mole % Cu(NO₃)₂TiO₂ nanoparticle formulation was 191 m²/g.

[0098] 4. Procedure

[0099] Nanoparticle metal oxides prepared in Parts 1-3 of this Examplewere tested for their abilities to destructively sorb or decontaminatebiological warfare mimics. In each trial run, nitrocellulose membraneswere inoculated with 200 μl B. subtilus spores solution or a gramnegative bacteria (E. coli or E. herbicola) suspension and allowed todry for approximately 1 hour. After 1 hour, each membrane was inoculatedwith 0.5 g of nanoparticles. Samples were taken at different timeintervals. After the desired contact time was reached, the membraneswere rinsed in 10 ml of PBS to elute the spores. Next, 200 μl of thefinal solution was plated onto nutrient agar plates and incubated for 24hours at 37° C. Colonies were counted and compared to the controls todetermine the percent kill.

[0100] 5. Results

[0101] Tables 6-8 set forth these results. Table 6 illustrates that themetal oxides were able to inactivate bacterial spores, while Tables 7and 8 indicate that metal oxides readily decontaminate or destroygram-negative bacteria, even in less than an hour or a matter ofminutes. TABLE 6 Decontamination of B. subtilis Spores UsingNanoparticle Powders [Ce(NO₃)₃- Metal Oxide ZnO CuO Cu(NO₃)₂]TiO₂Surface area 153 m²/g 135 m²/g 191 m²/g Amount 0.5 g 0.5 g 0.5 g Time(minutes) Percent Kill Percent Kill Percent Kill 10 84.6 −− 95 20 88.2−− 97 30 97.2 −− 83 45 −− −− 84 60 −− 99.6 81

[0102] TABLE 7 Decontamination of E. coli and Erwinia herbicola AfterExposure to Nanoparticles for 24 Hours Metal Oxide AP-MgO AP-CaOAP-MgO/ZnO^(a) CP-MgO/ZnO^(b) Amount 0.5 g 0.5 g 0.5 g 0.5 g PercentPercent Bacteria Kill Kill Percent Kill Percent Kill E. coli 100 100 100100 E. herbicola 40 100 100 100

[0103] TABLE 8 Decontamination of Erwinia herbicola After Exposure toNanoparticles for 1 Hour Metal Oxide AP-MgO AP-MgO CP-MgO AP-MgO/ZnOAmount 0.5 g 0.5 g 0.5 g 0.5 g Bacteria Percent Kill Percent KillPercent Kill Percent Kill E. herbicola 100 93 100 79

EXAMPLE 10

[0104] 1. Procedure

[0105] In this example, metal oxide nanoparticles (in a propellant) weretested for their abilities to decontaminate various textured surfaces.The concentration of B. subtilus spores was first determined by platingserial dilutions of the stock solution and counting the number ofcolonies that appeared on the corresponding plates. A concentration of1.40×10⁸ CFU/ml was obtained. The solution was then placed in a spraybottle to disperse the spores onto the various surfaces. The multiplepanes were placed into the biochamber for safety precautions. Each panelwas contaminated with a concentration of spores that was about 1.4×10⁸CFU/ml. The spores were allowed to dry on the panels for 24 hours beforedecontamination took place. After the drying period, the panels weresprayed with a solution containing metal oxide nanoparticles (2 grams ofpowder in 200 ml of either pentane or water) via a hand-held tankcompressed with nitrogen gas. After the 24-hour decontamination period,the panels were tested using a PBS moistened swab. The swab was thenplaced into 20 ml of PBS, and the solution was allowed to elute for 30minutes. The solution was serially diluted 10⁻¹, 10⁻², 10⁻³, 10⁻⁴, 10⁻⁵,and 10⁻⁶, respectively, in 9 ml of PBS and 200 μl of each dilution wasplated onto nutrient agar in triplicate to evaluate growth. After the24-hour incubation period, the colonies were counted, and the percentkill was calculated for each textured panel.

[0106] 2. Results

[0107] Table 9 sets forth these results. AP-MgO was successful withevery surface except the office panel. Overall, ZnO in water did notdecontaminate as well as the AP-MgO, but it was able to successfullydecontaminate the office panel and was also better at decontaminatingthe metal panel. These results should be even better with a solutioncontaining higher concentrations of the nanoparticles. TABLE 9 TexturedSurface AP-MgO in Pentane ZnO in Water Wallboard 98 63 Metal Panel 85 92Ceiling Tile 91 84 Office Panel 0 92 Cement 99 64 Carpet 99 81

EXAMPLE 11

[0108] 1. Procedure

[0109] A suspension of tryptone yeast extract (TYE) broth was preparedwith a single colony from a E. coli (C3000, ATCC#15597) plate andincubating it for 18 hours at 37° C. The lysate was treated with AP-MgOby adding 0.009 g of powder/700 μl of diluted MS2 virus (a simulant ofhuman enteric viruses). Approximately 300-500 μl of the E. coli and 100μl of the treated lysate were added to a tube containing 2.5 ml TYE softagar. The solution was placed in a water bath (50° C.) for approximately10 minutes and poured onto a TYE agar plate that was allowed to dry forapproximately 10 minutes followed by incubation at 37° C. This procedurewas performed in serial dilutions up to a dilution of 10⁻¹⁰. Thedilutions of 10⁻⁸ to 10⁻¹⁰ were plated for counting. The plaques werethen counted, and the degree of killing was determined by comparing thenumber of countable plaque-forming units on the controls to the onescontaining AP-MgO nanoparticles.

[0110] 2. Results

[0111] The AP-MgO significantly affected the growth of the MS2 virus.These results are set forth in Table 10. Between three differentdilution experiments, the lowest and highest percent kills were 96.5%and 100%, respectively. TABLE 10 Control Decontaminated DecontaminatedExperi- Plaques Dilution Plaques Dilution % % ment^(a) (average) Factor(average) Factor Recovery Kill Trial 1 76.3 8 2.67 8 3.50 96.5 Trial 274 9 0 9 0 100.0 Trial 3 109 10 1 10 0.917 99.08

We claim:
 1. A mixture adapted for placement within a container, saidmixture comprising: particles selected from the group consisting ofmetal oxide particles, metal hydroxide particles, and mixtures thereof,said particles having a surface area of at least about 70 m²/g; and apropellant.
 2. The mixture of claim 1, said metal oxides being selectedfrom the group consisting of MgO, CeO₂, AgO, SrO, BaO, CaO, ZnO, Al₂O₃,ZrO₂, FeO, V₂O₃, V₂O₅, Mn₂O₃, Fe₂O₃, NiO, CuO, and Ag₂O and mixturesthereof.
 3. The mixture of claim 2, said metal oxide comprising MgO. 4.The mixture of claim 1, said mixture including a suspension agent forsaid particles.
 5. The mixture of claim 4, said suspension agentselected from the group consisting of pentane and water.
 6. The mixtureof claim 1, said particles comprising metal oxide composites made up ofa first metal oxide at least partially coated with a second, differentmetal oxide.
 7. The mixture of claim 1, said particles being present asa self-sustaining body formed of a plurality of agglomerated particles.8. The mixture of claim 1, said propellant being nitrogen gas.
 9. Amixture adapted for placement within a container, said mixtureconsisting essentially of particles selected from the group consistingof metal oxide and metal hydroxide particles and mixtures thereof, asuspension agent for said particles, and a propellant.
 10. The mixtureof claim 9, said metal oxide and metal hydroxide parties eachrespectively selected from the group consisting of alkali metal,alkaline earth metal, transition metal, and lanthanide oxides andhydroxides and mixtures thereof.
 11. The mixture of claim 10, said metaloxides being selected from the group consisting of MgO, CeO₂, AgO, SrO,BaO, CaO, ZnO, Al₂O₃, TiO₂, ZrO₂, FeO, V₂O₃, V₂O₅, Mn₂O₃, Fe₂O₃, NiO,CuO, SiO₂, and Ag₂O and mixtures thereof.
 12. The mixture of claim 11,said metal oxide being MgO.
 13. The mixture of claim 9, said suspensionagent selected from the group consisting of pentane and water.
 14. Anon-aqueous mixture adapted for placement within a container, saidmixture comprising particles selected from the group consisting of metaloxide and metal hydroxide particles and mixtures thereof, said particleshaving an average crystallite size of up to about 20 nm, and apropellant.
 15. The mixture of claim 14, said metal oxide and metalhydroxide parties each respectively selected from the group consistingof alkali metal, alkaline earth metal, transition metal, and lanthanideoxides and hydroxides, and mixtures thereof.
 16. The mixture of claim15, said metal oxides being selected from the group consisting of MgO,CeO₂, AgO, SrO, BaO, CaO, ZnO, Al₂O₃, TiO₂, Zro₂, FeO, V₂O₃, V₂O₅,Mn₂O₃, Fe₂O₃, NiO, CuO, SiO₂, and Ag₂O and mixtures thereof.
 17. Themixture of claim 16, said metal oxide being MgO.
 18. The mixture ofclaim 14, said mixture including a suspension agent for said particles.19. The mixture of claim 18, said suspension agent selected from thegroup consisting of pentane and water.
 20. A method of at leastpartially decontaminating an area subjected to an undesirable chemicalor biological agent, comprising the step of spraying the mixture ofclaim 1 adjacent said area.
 21. The method of claim 20, said areacomprising a surface.
 22. The method of claim 21, said surfacecomprising a textured surface of a member selected from the groupconsisting of wallboard, metal panel, ceiling tile, office panel,cement, and carpet.
 23. The method of claim 20, said undesirablechemical or biological agent being an airborne agent.
 24. A method of atleast partially decontaminating an area subjected to an undesirablechemical or biological agent, comprising the step of spraying themixture of claim 9 adjacent said area.
 25. A method of at leastpartially decontaminating an area subjected to an undesirable chemicalor biological agent, comprising the step of spraying the mixture ofclaim 14 adjacent said area.